Final answer:
Bulk flow allows plants to move water from roots to leaves through the xylem without energy input, utilizing water potential differences created by evapotranspiration, and leveraging capillary action as well as the adhesion and cohesion of water.
Step-by-step explanation:
Plants transport water from their roots to their leaves through a process known as bulk flow, which occurs in the specialized vascular tissue called xylem. This movement does not require any direct energy input from the plant because it relies on the physical properties of water and the structure of the plant tissues. Water moves from areas of higher water potential, typically the roots where water is absorbed from the soil, to areas of lower water potential, such as the leaves where water vapor is lost to the atmosphere through evapotranspiration. The loss of water from the leaves creates a negative pressure within the xylem, effectively pulling water upward from the roots through the tiny rigid tubes made of cellulose. Capillary action, adhesion, and cohesion work together to facilitate this ascent of water, nourishing the plant and enabling it to perform photosynthesis.